The modern lifestyle has become increasingly dependent upon the use and existence of fossil fuels such as coal, petroleum and natural gas. In fact, more than half of all power consumed since the industrial revolution has occurred in only the last two decades, with more than 80% derived from the combustion of fossil fuels. In the United States, these fuels accounts for nearly two-thirds of the total electricity produced and the vast majority of all energy used for transportation.
Due to the ubiquitous consumption of fossil fuels, supplies of this non-renewable energy source are dwindling as environmental problems continue to mount. The burning of fossil fuels produces many environmentally-significant byproducts, including carbon dioxide, a greenhouse gas that traps heat in the earth's atmosphere. Over the last 150 years, burning fossil fuels has resulted in more than a 25% increase in the amount of carbon dioxide in the earth's atmosphere and more than 90% of U.S. greenhouse gas emissions is the result of such combustion. Moreover, other poisonous gasses such as carbon monoxide, nitrogen oxides, sulfur oxides, and hydrocarbons released during combustion of these fuels have reduced air quality throughout the world.
These pollution-related concerns, coupled with high oil prices, increased political tension with the worlds' largest petroleum suppliers, and increasing government support have lead to a number of advances in large-scale renewable energy technologies capable of harnessing energy from natural, constantly-replenished sources, such as solar power, water waves and tides, wind, and hydrogen. Fortunately, the use of renewable energy technologies, such as wind and water turbines, has increased over the past decade due to decreased costs of both production and deployment and increases in efficiency. However, many conventional wind and water turbines still require large amounts of capital to produce and require both special machinery and large amounts of real estate for deployment and use. As such, the use of such technology in rural and remote areas, where energy may be crucial for survival or just desired for recreation, has mostly been prevented.
U.S. Patent Publication No. 2010/0148512 to Pitre, discloses an in-stream apparatus for generating electricity from fluid flows, such as shallow river and tidal flows. The invention is said to comprise a generator housed in a prolate-shaped (i.e. football-shaped) buoyant casing around which two helicoid-shaped blades are wound. The helicoid-shaped blades are interleaved, and the entire apparatus is aligned such that the casing and axis of rotation are generally said to be parallel with the fluid stream.
U.S. Pat. No. 5,411,422 to Robertson discloses a propeller comprising a one piece blade that spirals out from an angular solid hub portion as a continuous screw spiral. The propeller comprises a circular hub having an axial space around which the spiral screw portion winds. The spiral screw is said to have a helix configuration which defines an axial void through its center and is further said to increase in circumference as the distance from the hub increases.
U.S. Patent Publication No. 2001/0000197 to Gorlov describes a helical turbine assembly capable of providing high speed unidirectional rotation under a multidirectional ultra low-head fluid flow. The turbine is said to comprise a plurality of airfoil-shaped helical turbine blades supported for rotation on a rotatable shaft. Further, the entire blade combination is disclosed as being mounted for rotation within a protective cage structure.
Accordingly, there is a need in the art for an apparatus and method to allow renewable energy to be harnessed in remote or rural areas, without requiring the use of special equipment or more than a single person. In addition to portability, there is a need for such an apparatus to be durable, safe to handle and use, and relatively inexpensive to both produce and maintain. It would be beneficial if such an apparatus was capable of producing usable power in low-flow velocity environments such as slow moving streams or when pulled behind a sailboat.